TriuIndx

Returns the indices of upper triangle part of a matrix.

Interface 1

܀ Interface

 INTERFACE
  MODULE PURE FUNCTION TriuIndx(m, n, diagNo) RESULT(ans)
    INTEGER(I4B), INTENT(IN) :: m
    !! number of rows
    INTEGER(I4B), OPTIONAL, INTENT(IN) :: n
    !! number of columns, default = m
    INTEGER(I4B), OPTIONAL, INTENT(IN) :: diagNo
    !! diagonal number, default = 0
    !! diagNo>0 means super diagonal
    !! diagNo<0 means subdiagonal
    INTEGER(I4B), ALLOCATABLE :: ans(:, :)
    !! ans(:,1) contains the row indices
    !! ans(:,2) contains the col indices
  END FUNCTION TriuIndx
END INTERFACE 

️܀ See example

program main
use easifemBase
implicit none

BLOCK
INTEGER(I4B), ALLOCATABLE :: indx(:,:)
CALL Display(TriuIndx(m=3,n=3,diagNo=0), "(3,3) diagNo=0, = " )
CALL Display(TriuIndx(m=3,n=3,diagNo=1), "(3,3) diagNo=1, = " )
CALL Display(TriuIndx(m=3,n=3,diagNo=2), "(3,3) diagNo=2, = " )
END BLOCK

See results

(3,3) diagNo=0, =
------------------
       1  1
       2  2
       3  3
       1  2
       2  3
       1  3

(3,3) diagNo=1, =
------------------
       1  2
       2  3
       1  3

(3,3) diagNo=2, =
------------------
       1  3

BLOCK
CALL Display(TriuIndx(m=3,n=3,diagNo=-1), "(3,3) diagNo=-1, = " )
CALL Display(TriuIndx(m=3,n=3,diagNo=-2), "(3,3) diagNo=-2, = " )
END BLOCK

See results

(3,3) diagNo=-1, =
-------------------
       2  1
       3  2
       1  1
       2  2
       3  3
       1  2
       2  3
       1  3
(3,3) diagNo=-2, =
-------------------
       3  1
       2  1
       3  2
       1  1
       2  2
       3  3
       1  2
       2  3
       1  3

end program main

↢

Interface 2

܀ Interface

INTERFACE
  MODULE PURE FUNCTION TriuIndx(A, diagNo) RESULT(ans)
    CLASS(*), INTENT(IN) :: A(:, :)
    INTEGER(I4B), OPTIONAL, INTENT(IN) :: diagNo
    !! diagonal number, default = 0
    !! diagNo>0 means super diagonal
    !! diagNo<0 means subdiagonal
    INTEGER(I4B), ALLOCATABLE :: ans(:, :)
    !! ans(:,1) contains the row indices
    !! ans(:,2) contains the col indices
  END FUNCTION TriuIndx
END INTERFACE

️܀ See example

program main
use easifemBase
implicit none
INTEGER(I4B), ALLOCATABLE :: indx(:,:)
REAL( DFP ) :: amat(3,3)

CALL Display(TriuIndx(amat,diagNo=0), "(3,3) diagNo=0, = " )
CALL Display(TriuIndx(amat,diagNo=1), "(3,3) diagNo=1, = " )
CALL Display(TriuIndx(amat,diagNo=2), "(3,3) diagNo=2, = " )
CALL Display(TriuIndx(amat,diagNo=-1), "(3,3) diagNo=-1, = " )
CALL Display(TriuIndx(amat,diagNo=-2), "(3,3) diagNo=-2, = " )

See results

(3,3) diagNo=0, = 
------------------
       1  1       
       2  2       
       3  3       
       1  2       
       2  3       
       1  3       
(3,3) diagNo=1, = 
------------------
       1  2       
       2  3       
       1  3       
(3,3) diagNo=2, = 
------------------
       1  3       
(3,3) diagNo=-1, = 
-------------------
       2  1        
       3  2        
       1  1        
       2  2        
       3  3        
       1  2        
       2  3        
       1  3        
(3,3) diagNo=-2, = 
-------------------
       3  1        
       2  1        
       3  2        
       1  1        
       2  2        
       3  3        
       1  2        
       2  3        
       1  3        

end program main

↢